Molly Munger, a wealthy attorney and civil rights advocate, talks to reporters about her proposed ballot initiative to raise income taxes for school funding following her appearance at the California Parent Teacher Association's annual meeting in Sacramento, Calif., Monday, Feb. 6, 2012. Munger's plan is one of three proposals for the November ballot that would raise taxes to help pay for education. (AP Photo/Rich Pedroncelli)

Photo: Rich Pedroncelli, Associated Press

Molly Munger, a wealthy attorney and civil rights advocate, talks...

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Molly Munger, a wealthy attorney and civil rights advocate, outlined her proposed ballot initiative to raise income taxes for school funding during an appearance at the California Parent Teacher Association's annual meeting in Sacramento, Calif., Monday, Feb. 6, 2012. Munger's plan is one of three proposals for the November ballot that would raise taxes to help pay for education. (AP Photo/Rich Pedroncelli)

Supporters of two ballot initiatives that would raise taxes to fund public education and other services said on Monday they will not back down from those efforts, upending Gov. Jerry Brown's crusade to clear the November ballot of any competing tax measures.

Backers of the so-called "Millionaires Tax" officially began a signature-gathering effort Monday, while the wealthy proponent of another measure, speaking to the California State PTA in Sacramento, pledged that she would spend millions to get her initiative on the ballot.

Those actions could significantly undermine Brown's efforts, as voters are known to reject all tax measures when faced with multiple initiatives.Molly Munger, a wealthy civil rights attorney from Southern California whose family is worth billions, rejected the notion that she or others should show deference to Brown by letting his tax measure be the only one on November's ballot.

"I don't think we'd have a very good functioning democracy if we always just did what one person at the top wanted," Munger told reporters after presenting her plan to members of the state PTA, which has endorsed the measure. She received an extended standing ovation after her remarks.

She added that, "In fact, one of the reasons we have democracy is because that old method, which is to just do what the king says, led to some very bad decisions over time."

Under Munger's plan, called "Our Children, Our Future," the income tax for everyone in California would increase, though with the largest increases on the highest wage earners. She estimates the proposal would generate $10 billion a year that would be dedicated solely to education, with criminal penalties if lawmakers try to adjust that. It would expire after 12 years.

Another version would dedicate some of the money to pay back the state's debt for the first few years, and Munger said backers have yet to decide which to pursue. Munger has been the sole large contributor to the effort so far, giving $800,000, according to the secretary of state.

'Millionaires tax'

The other measure, for which proponents started a signature-gathering effort Monday, would increase income taxes on people who earn more than $1 million a year in California. Backers estimate that would generate about $9.5 billion annually, with the bulk dedicated to education. Health services and public safety would get some of the new revenue as well. It has no expiration date.

That measure, "The Millionaires Tax of 2012," is supported by the California Federation of Teachers, the Courage Campaign, the California Nurses Association and others. Leaders of the effort, along with Munger on her initiative, said they had not personally heard from the governor with a pitch to end their efforts.

Both also expressed confidence that conventional wisdom is wrong and that one or more tax measures could pass even with multiple initiatives on the ballot.

"We're not concerned that there will be multiple measures on the ballot," said Joshua Pechthalt, president of the California Federation of Teachers, adding that he had confidence voters would "be able to decide which makes sense for them."

They have raised $700,000 so far in donations from groups sponsoring the measure, according to the secretary of state.

Circular firing squad

But Brown's top political adviser, Steve Glazer, said the probable impact of multiple measures is that all would receive diminished support, something he compared to a circular firing squad. He said the governor would continue trying to persuade them to drop their bids, but there is not much he can do.

"This is in their control. They are making these choices," Glazer said, adding that "they get to fully bear the consequences of their actions" if the measures fail.

Brown's plan would increase the sales tax by half a cent along with the income tax on the state's highest earners for five years.

Brown's effort has raised nearly $2.2 million so far, according to the secretary of state, with large donations from Indian tribes, the health care industry, unions and others.

He predicted that Brown would work to persuade these other groups to back off until the day they file signatures to place the measures on the ballot "because he understands the larger obstacle it creates."

"If nothing else, it reveals, if not confusion, certain divisions on the tax-and-spend side," he said. "And if there are divisions on the tax-and-spend side, for those of us who are fiscal conservatives, that can help politically."